Device and method for selectively milling the surface of a roadway

ABSTRACT

A device for cutting rumble strip grooves in a roadway. The device includes a cutter head on which is mounted a plurality of cutting teeth. The cutter head is symmetrically disposed around a center axis. At least one motor is provided for rotating the cutter head about its center axis. In addition to the motors that directly rotate the cutter head, a mechanism is provided for cycling the center axis of the cutter head through a continuous pathway. Accordingly, the cutter head experiences two separate rotations. The cutter head rotates about its own center axis. Meanwhile, the center axis is orbiting in a circular pathway. As the cutter head cycles through part of the continuous pathway, the cutter head contacts the roadway and cuts a rumble strip groove in the roadway.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to machines that are designed toremove material from the surface of a roadway with a rotating millinghead. More particularly, the present invention relates to such machinesthat can be configured to create parallel grooves in a roadway that canact as rumble strips.

[0003] 2. Prior Art Statement

[0004] Every year many vehicular accidents are caused by drivers who areinattentive or fall asleep while driving. Often, such accidents resultin severe injuries or loss of life. Different transportation authoritiesthroughout the country have tried many different programs to reduce theoccurrence of such accidents. Many roadside signs have been posted,reminding drivers to stay alert. Flashing lights are used alongdangerous parts of many roadways to try to get a driver's attention, andfocus that attention on driving. However, such passive devices have onlya limited likelihood of success in arousing a sleepy or inattentivedriver.

[0005] Recognizing the faults of passive systems, many transportationauthorities now use the active system of rumble strips to arouse sleepyor inattentive drivers. “Rumble strip” is the name used in thetransportation industry for parallel structures placed in the roadway.The parallel structures can either be depressions that are cut into thesurface of the roadway or protrusions that extend above the roadway.Rumble strips are placed on the side of the road to warn a driver thathis/her car is wandering off to the side of the road. Rumble strips arealso used before tollbooths and other changes in traffic patterns towarn drivers of the upcoming change. When the wheels of a vehicle passover a rumble strip, the driver of the vehicle physically experiences ahigh frequency vibration in the vehicle. Additionally, a loud rumblingnoise is created by the wheels passing over the rumble strips. Thecombination of the vibration and the noise actively awakes the driver ofthe vehicle. This hopefully arouses the driver to a point where thedriver can safely operate the vehicle.

[0006] Rumble strips can be created in a roadway as the roadway is beinglaid or repaved. However, most roadways that are in existence wereoriginally created without rumble strips. Accordingly, on many roadways,rumble strips are retroactively added to the structure of the roadway.Using current technologies, the most cost effective way to create rumblestrips in an existing roadway is to cut a series of parallel grooves inthe material of the roadway.

[0007] In the prior art, rumble strips on the side of a roadway aretraditionally made using a cylindrical cutter. The cylindrical cutter isperiodically raised and lowered into the surface of the roadway to cutthe desired grooves in the roadway.

[0008] As is well known by machinists, all cutting tools have an idealwork feed rate that optimizes the life of the cutting tool and thequality of the cut being made. If work is fed into a cutting tool tooquickly, the life of the cutting tool is dramatically shortened,Furthermore, if work is feed into a cutting tool too quickly, stressesoccur in the machine that drives the tool. This can cause the machine tobreak or prematurely require maintenance. This same principal applies tomilling machines that cut rumble strips into the material of a roadway.As has been previously mentioned, milling machines that cut rumblestrips on the side of a roadway contain cylindrical cutters. On theexterior of the cylindrical cutter are disposed many individual carbidecutting teeth. If the cylindrical cutter were to be advanced through thehard material of a roadway too rapidly, the carbide cutting teeth maybreak or wear rapidly. As a result, after only a short period of use,the carbide cutting teeth would have to be replaced.

[0009] To create ideal cutting conditions, a cylindrical cutting headwould be set in a stationary position over a segment of roadway andlowered into the material of the roadway at a controlled rate. After asingle groove was cut, the cylindrical cutter would be lifted andadvanced to the next set location of a cut. However, when creatingrumble strips on the side of a road, a rumble strip is formed aboutevery foot. Many hundreds of miles of rumble trips may be required to beinstalled in a typical construction job. If a milling machine were to beset in place for each cutting of the rumble strip, it would take far toomuch time to complete the job.

[0010] Recognizing the limitations of time, most all prior art rumblestrip milling machines operate using less than ideal cutting conditions.In many prior art rumble strip cutting machines, a rotating cylindricalcutter is attached to a vehicle and is rotated at a fixed revolutionrate. The cylindrical cutter is then periodically lifted and droppedinto the roadway as the vehicle moves forward. Accordingly, as thecylindrical cutter descends into the material of the roadway, it is alsobeing pulled forward through the material of the roadway, therebycreating an elongated groove. The faster the vehicle moves, the furtherthe cylindrical cutter is pulled through the roadway material and themore elongated the groove becomes.

[0011] If a vehicle travels too quickly, the rate at which the cuttingteeth advance into the roadway material may surpass the operationalspecifications for the cutting teeth. As a consequence, the cuttingteeth may break or wear prematurely. Additionally, if the vehicletravels too quickly, the grooves may become so elongated that there islittle uncut roadway left between each of the cut grooves. This createsrumble strips that do not match the specifications of the transportationauthority that require certain minimum distances between grooves.

[0012] To prevent these problems from occurring, most prior art rumblestrip milling machines run at slow speeds where they produce no morethan two rumble strips a second.

[0013] A need therefore exists for an improved rumble strip millingmachine that can run at higher speeds without creating poorly formedgrooves or creating unnecessary wear on the cutting teeth. This need ismet by the present invention as described and claimed below.

SUMMARY OF THE INVENTION

[0014] The present invention is a device for cutting rumble stripgrooves in a roadway. The device includes a cutter head on which ismounted a plurality of cutting teeth. The cutter head is symmetricallydisposed around a center axis. At least one motor is provided forrotating the cutter head about its center axis. In addition to themotors that directly rotate the cutter head, a mechanism is provided forcycling the center axis of the cutter head along a continuous pathway.Accordingly, the cutter head experiences two separate rotations. Thecutter head rotates about its own center axis. Meanwhile, the centeraxis is orbiting in a continuous pathway.

[0015] As the cutter head cycles through a part of the continuouspathway, the cutter head contacts the roadway and cuts a rumble stripgroove in the roadway. The cutter head is propelled along a section ofroadway by a vehicle. The vehicle moves in a first direction, therebygiving a forward velocity to the cutting head as it cuts into theroadway. The movement of the cutting head as it cycles through itscontinuous pathway compensates for the forward movement of the cuttinghead. As a result, the cutting head produces a high quality groove inthe roadway with reduced wear on the cutting head and its drivemechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For a better understanding of the present invention, reference ismade to the following description of exemplary embodiments thereof,considered in conjunction with the accompanying drawings, in which:

[0017]FIG. 1 is a side view of one exemplary embodiment of the presentinvention, shown in operation on a segment of roadway;

[0018]FIG. 2 is a perspective view of the primary rumble strip millingmachine components of the present invention;

[0019]FIG. 3 shows the relationship between the cylindrical cutter, theorbital disc and the surface of the roadway as the cylindrical cuttercycles through its continuous pathway of movement;

[0020]FIG. 4 shows the movement of the cylindrical cutter as it contactsand moves through the material of the roadway;

[0021]FIG. 5 shows a graph that plots the position of the cylindricalcutter verses the relative movement of the cutter in relation to thepavement being cut; and

[0022]FIG. 6 shows an exemplary embodiment of the mounting elements thatjoin the rumble strip milling machine to a vehicle.

DETAILED DESCRIPTION OF THE DRAWINGS

[0023] Although the present invention rumble strip milling machine canbe configured to be a separate trailer assembly that can be towed behinda powered vehicle, such as a truck, the present invention isparticularly well suited to be built as part of a powered vehicle.Accordingly, in the exemplary embodiment of the present invention shown,the rumble strip milling machine is shown as part of a dedicated vehiclein order to set forth the best mode contemplated for the invention.

[0024] Referring to FIG. 1, a first exemplary embodiment of the presentinvention rumble strip milling machine 10 is shown. The rumble stripmilling machine 10 is attached to the undercarriage of a self-poweredvehicle 12. The vehicle 12 is a dedicated piece of constructionequipment for use only at construction sites. Consequently, the powertrain of the vehicle 12 is designed to operate at peak efficiency whilepropelling the vehicle at its operational speeds, which is typicallybelow five miles per hour.

[0025] The rumble strip milling machine 10 is suspended from the bottomof the vehicle 12. The rumble strip milling machine 10 contains acylindrical cutter 20. A plurality of replaceable cutting teeth 22 areattached to the exterior of the cylindrical cutter 20. The cylindricalcutter 20 rotates in a direction opposite of that of the front wheels ofthe vehicle 12. Consequently, if the vehicle 12 is traveling forward,the cylindrical cutter 20 shown in FIG. 1 rotates clockwise in the planeof the paper.

[0026] The rumble strip milling machine 10 has a main frame 24 that issuspended below the vehicle 12 a predetermined distance D1 above thelevel of the pavement 18. This height can be selectively adjusted, aswill later be explained. The cylindrical cutter 20 partially extendsbelow the frame 24. The cylindrical cutter 20 periodically moves from afirst elevation above the pavement 18 to a second elevation below theplane of the pavement 18. As a result, the cylindrical cutter 20 cutsperiodic parallel groves 26 in the material of the pavement 18. Thespeed at which the cylindrical cutter 20 cycles above and then into thematerial of the pavement 18 is directly proportional to the forwardspeed of the vehicle 12. Accordingly, the rumble strip milling machine10 will create evenly spaced grooves 26 in the pavement 18 even if thespeed of the vehicle 12 were to vary.

[0027] Referring now to FIG. 2, the primary workings of the rumble stripmilling machine 10 are illustrated. The rumble strip milling machine 10has a cylindrical cutter 20 that does the cutting. On the exterior ofthe cylindrical cutter 20 are a plurality of cutting teeth 22. Each ofthe cutting teeth 22 is individually replaceable. Accordingly, if onecutting tooth were to break, that cutting tooth can be replaced. Thecutting teeth 22 on adjacent rows are staggered in position. However, itis preferred that the same pattern of cutting teeth 22 be repeated every90° on the periphery of the cylindrical cutter 20. In this manner, it isassured that the cutting teeth 22 on the cylindrical cutter 20 will makea full cutting pass for each quarter turn of the cylindrical cutter 20.

[0028] The cylindrical cutter 20 is concentrically mounted to a primarydrive shaft 30. The primary drive shaft 30 is connected to at least onedrive motor 32. In the shown embodiment, both ends of the primary driveshaft 30 are connected to separate drive motors 32. The use of two drivemotors 32 enables a high degree of horsepower to be obtained from twosmall motors rather than through the use of one large bulky motor. Theuse of two motors also provides a degree of side-to-side balance to theassembly that prevents wobbling during its operation. The drive motors32 can be electric motors or combustion motors. However, in thepreferred embodiment, hydraulic motors are used because they have a veryhigh power-to-weight ratio. The use of lightweight motors is importantto reduce vibrational dynamics, as will later be explained.

[0029] At least one orbiter disc 34 is provided. Each orbiter disc 34 iseither a belt wheel or a gear having a circular outer periphery and aninner aperture 36 that is eccentrically positioned relative the circularouter periphery. The primary drive shaft 30 passes through the eccentricinner aperture 36. In the eccentric inner aperture 36 is a bearing pack(not shown) that enables the primary drive shaft 30 to rotate freelywithin the eccentric inner aperture 36. Since the primary drive shaft 30passes through the eccentric inner aperture 36 of each orbiter disc 34,each orbiter disc 34 is not symmetrically disposed around the primarydrive shaft 30.

[0030] A secondary drive shaft 38 is provided. The secondary drive shaft38 is coupled to a speed synchronized drive 40. The speed synchronizeddrive 40 is a drive mechanism that turns the secondary drive shaft 38 ata speed that is directly proportional to the forward speed of thevehicle 12 (FIG. 1). Consequently, the faster the vehicle 12 is movingforward, the faster the speed synchronized drive 40 will turn thesecondary drive shaft 38. The speed synchronized drive 40 can be ahydraulic drive, an electric drive or a mechanical drive that is drivenby some portion of the power train or wheels of the vehicle 12 (FIG. 1).

[0031] The secondary drive shaft 38 is mechanically coupled to theorbiter discs 34 that are positioned around the primary drive shaft 30.If the orbiter discs are gears, the mechanical connection between theorbiter discs and the secondary drive shaft 38 can be accomplished usingconnecting gears. However, in the shown embodiment, the orbiter discs 34are belt wheels. As such, the orbiter discs 34 are connected to smallerbelt wheels 42 on the secondary drive shaft 38 with the use of drivebelts 44.

[0032] It will therefore be understood that the speed synchronized drive40 turns the secondary drive shaft 38 at a rotation rate that isdirectly proportional to the forward speed of the vehicle 12 (FIG. 1).The secondary drive shaft 38 turns the obiter discs 34. The orbiterdiscs 34 physically move the primary drive shaft 30 through a circularrange of motion as the primary drive shaft 30 spins. Accordingly, thecylindrical cutter 20 experiences two rotational motions. First, thecylindrical cutter is rotating around the primary drive shaft 30.Secondly, the primary drive shaft 30 is moved through a circular rangeof motion by the orbiter discs 34. Consequently, the cylindrical cutteris rotating about a first axis while that first axis orbits around asecond axis.

[0033] The cylindrical cutter 20 is rotated around the primary driveshaft 30 by the drive motors. The primary drive shaft 30 and drivemotors are orbited in a circular range of motion by the orbiter discs34. Since the drive motors 32 are orbiting through the circular range ofmotion, the drive motors 32 become sources of dynamic vibration. Byminimizing the weight of the drive motors 32, the degree of dynamicvibration is also reduced. Thus, it is desirable to have very low weightdrive motors 32. To counteract the dynamic vibrations created by themovement of the drive motors 32, counterweights 46 are provided. Thecounterweights 46 are calibrated in size and location to counteract thedynamic vibrations of the moving drive motors 32.

[0034] Referring now to FIG. 3, the movement in the primary drive shaft30 created by the rotation of the orbiting disc 34 is better understood.By referring to FIG. 3 simultaneously, it can be seen that the center Cof the orbiting disc 34 remains at a constant height H1 above thepavement 18 as the orbiting disc 34 is rotated by the secondary driveshaft 38 (FIG. 2). However, the position that the orbiting disc 34supports the primary drive shaft 30 changes.

[0035] Looking at Position 1 in FIG. 3, the orbiting disc 34 is shownsupporting the primary drive shaft 30 at its highest point above thelevel of the pavement. At this position, it can be seen that the primarydrive shaft 30, and thus the center of the cylindrical cutter 20, issupported above the constant height H1 of the center of the orbiter disc34. In this position, the center of the primary drive shaft 30 and thecenter of the cylindrical cutter 20 are also vertically aligned with thecenter of the orbiter disc 34. Once in such an orientation, the cuttingteeth 22 on the cylindrical cutter 20 are supported well above thesurface of the pavement. Consequently, the cylindrical cutter 20 doesnot cut into the pavement.

[0036] Referring to Position 2 in FIG. 3, it can be seen that as theorbiter disc rotates 90° in a clockwise direction, the primary driveshaft 30 and the center of the cylindrical cutter 20 are lowered to thesame height H1 as the center of the orbiter disc 34. However, the centerof the orbiter disc 34 is no longer vertically aligned with the centerof both the primary drive shaft 30 and the cylindrical cutter 20.Rather, the primary drive shaft 30 and the cylindrical cutter 20 havemoved in the x-axis and are now horizontally aligned with the center ofthe orbiter disc 34. At this location, the cylindrical cutter 20 is muchcloser to the surface of the pavement but has not yet made contact withthe surface of the pavement.

[0037] Referring to Point 3 in FIG. 3, it can be seen that as theorbiter disc 34 rotates 180° from its starting position in a clockwisedirection, the primary drive shaft 30 and the center of the cylindricalcutter 20 are closest to the level of the pavement. At this position,the center of the cylindrical cutter 20 is below the center of theorbiter disc 34. Furthermore, the center of both the primary drive shaft30 and the cylindrical cutter 20 again vertically align with the centerof the orbiter disc 34. As the cylindrical cutter 20 moves into Point 3,it descends below the level of the pavement, thereby creating thedesired groove.

[0038] Referring lastly to Position 4 in FIG. 3, it can be seen that asthe orbiter disc 34 rotates yet another 90° in a clockwise direction toa position 270° beyond its starting point, the primary drive shaft 30and the center of the cylindrical cutter 20 are again raised to the sameheight H1 as the center of the orbiter disc 34. However, the center ofthe orbiter disc 34 is no longer vertically aligned with the center ofboth the primary drive shaft 30 and the cylindrical cutter 20. Rather,the primary drive shaft 30 and the cylindrical cutter 20 have moved inthe x-axis and are again horizontally aligned with the center of theorbiter disc 34. At this position, the cylindrical cutter 20 has beenraised above the surface of the pavement and no longer makes contactwith the surface of the pavement. Lastly, the orbiter disc rotates alast 90° and the cylindrical cutter 20 is moved back into theorientation of Position 1.

[0039] Referring now to FIG. 4 in conjunction with FIG. 3, it can beseen that as the cylindrical cutter cycles through the point positionsshown in FIG. 3, the center of the cylindrical cutter 20 follows agenerally sinusoidal pathway 50 (FIG. 4). Point 1 in FIG. 3 correspondsto the top of a crest in the sinusoidal pathway 50 shown in FIG. 4.Point 3 in FIG. 3 corresponds to the bottom of a trough in thesinusoidal pattern of FIG. 4. Point 2 and Point 4 in FIG. 3,respectively correspond to halfway points where the cylindrical cutter20 is either ascending a crest or descending a trough in the sinusoidalpathway 50.

[0040] The cylindrical cutter 20 is rotating about its own center. Thecenter of the cylindrical cutter 20 is being orbited around a secondaryaxis. Furthermore, the cylindrical cutter 20 is attached to a vehiclethat has forward velocity. The result of all of these movements createsthe sinusoidal pathway of motion shown in FIG. 4. When the cylindricalcutter 20 contacts the pavement, there is a complex degree of relativemovements that exists between the cylindrical cutter and the roadway. Assoon at the cylindrical cutter contacts the roadway, the cylindricalcutter cuts into to material of the roadway. This cut is elongated bythe relative movement between the cylindrical cutter and the roadwaycaused by the forward velocity of the vehicle that supports thecylindrical cutter. However, due to the secondary orbit motion of thecylindrical cutter, the cylindrical cutter moves back in the directionof the passing payment, thereby reducing the elongation that occurs.

[0041] Referring to FIG. 5, a graph is shown that plots the position ofthe cylindrical cutter relative to the passing payment. As can be seenfrom FIG. 5, it can be seen that the cylindrical cutter onlyperiodically descends below the roadway surface. However, when incontact with the roadway surface the cylindrical cutter has very littlerelative forward movement with respect to the pavement.

[0042] It will therefore be understood that any groove made by thecylindrical cutter does not have a radius of curvature that matches thatof the cylindrical cutter. Rather, the radius of curvature of a cutgroove is slightly larger than that of the cylindrical cutter. Thecylindrical cutter does not just descend directly vertically into thematerial of the pavement. Rather, the cylindrical cutter moves slightly,in the direction of the passing pavement, as it cuts into the materialof the pavement. The movement of the cylindrical cutter dramaticallydecreases the elongation of the cut groove caused by the forwardmovement of the vehicle that supports the cylindrical cutter. At avehicle operational speed of between 2 miles per hour and five miles perhour, the elongation of the groove caused by the forward velocity of thevehicle does not exceed ½ inch.

[0043] Since the movement of the cylindrical cutter compensates for theforward movement of the vehicle, the cylindrical cutter is notsignificantly pulled through the material of the roadway by the forwardmovement of the vehicle. The result is that front-to-back movement ofthe cylindrical cutter as it cuts provides a cutting relief for thecutting teeth. This prevents the cutting teeth from cutting into thematerial of the roadway at too rapid a feed rate, thereby significantlyprolonging the useful life of each of the cutting teeth and reduces thenumber of cutter teeth that break prematurely.

[0044] Referring now to FIG. 6, it will be understood that the rumblestrip milling machine 10 is not rigidly mounted to its support vehicle.Rather, the rumble strip milling machine 10 is supported in a mannerthat enables the overall assembly to be free floating. In FIG. 6, it canbe seen that the weight of the rumble strip milling machine 10 issupported by two primary support arms 52, 54 and a vertical adjustmentcylinder 56. The two primary support arms 52, 54 are joined to the frameof the vehicle at pivot points. The vertical adjustment cylinder 56 iscoupled to the top of the rumble strip milling machine 10. As a result,as the vertical adjustment cylinder 56 contracts and expands, the twoprimary support arms 52, 54 rotate about the pivot points, therebyraising and lowering the overall rumble strip milling machine 10 to anyselected height.

[0045] The structure of either one or both of the two primary supportarms 52, 54 can include adjustable cylinders 58. Such adjustablecylinders 58 can be used to control the pitch, tilt and yaw of therumble strip milling machine 10 in order to match the contour of aroadway that may be inclined or otherwise sloped.

[0046] Returning to FIG. 1, it will now be understood that the height ofthe rumble strip milling machine 10 is controlled by the driver of thevehicle 12. Accordingly, should the driver of a vehicle 12 approach ametal expansion joint on a roadway, the rumble strip milling machine 10can be raised over the expansion joint without the driver of the vehicle12 ever having to exit the vehicle 12 or even stop the forward progressof the vehicle 12.

[0047] It will be understood that the embodiment of the presentinvention specifically described and illustrated is merely exemplary andthe shown embodiments can be modified in many ways. For example, therumble strip milling machine can be made part of a cart that is pulledbehind a truck. Details such as the length and the diameter of thecylindrical cutter and the rotating speed of the cylindrical cutter canbe altered to match the needs of a contractor and the material of theroadway. All such alternate embodiments and variations are intended tobe included within the scope of the claims as listed below.

What is claimed is:
 1. A device for cutting rumble strip grooves inpavement, comprising: a cutter head having a plurality of cutting teeththereon, said cutter head having a first diameter and a center axis; atleast one motor for rotating said cutter head about said center axis; amechanism for continuously cycling said center axis of said cutter headthrough a continuous pathway, wherein said cutter head contacts thepavement and cuts a rumble strip groove in the pavement as said cutterhead cycles through part of said continuous pathway.
 2. The deviceaccording to claim 1, further including a vehicle for moving said cutterhead along a roadway at a selected forward velocity.
 3. The deviceaccording to claim 1, wherein said mechanism cycles said central axis ofsaid cutter head through said continuous pathway at a cycle rate that isdirectly proportional to said selected forward velocity.
 4. The deviceaccording to claim 1, wherein said cutter head is a cylindrical cutterhaving a drive shaft coupled to said center axis, wherein said driveshaft is rotated by said at least one motor.
 5. The device according toclaim 3, wherein said mechanism includes at least one orbiter disc, andeach said orbiter disc has a center point, wherein said drive shaftpasses through each said orbiter disc at a point eccentric from saidcenter point.
 6. The device according to claim 5, wherein each saidorbiter disc is free to rotate about said drive shaft, independent ofsaid drive shaft.
 7. The device according to claim 6, wherein saidmechanism includes a power source to rotate said orbiter disc, therebycausing said drive shaft and said center axis of said cutter head tomove through said continuous pathway.
 8. The device according to claim2, wherein said cutter head cycles through said continuous pathway inthe same direction of rotation as the wheels of said vehicle, as saidvehicle moves forward.
 9. The device according to claim 8, wherein saidcutter head is rotated by said at least one motor in a directionopposite the direction of rotation of said continuous pathway.
 10. Amethod of cutting rumble strips in pavement, comprising the steps of:providing a cutter head; rotating said cutter head about a central axis;cycling said central axis through a continuous pathway as said cutterhead rotates, wherein said cutter head enters the roadway and cuts agroove in the roadway as it cycles through part of said continuouspathway.
 11. The method according to claim 10, further including thestep of propelling said cutter head at a selected direction and speedalong said pavement as said cutter head rotates and is cycled throughsaid continuous pathway, wherein said cutter head cuts a new section ofpavement each time said cutter head cycles through said continuouspathway.
 12. The method according to claim 10, further including thestep of cycling said cutter head through said continuous pathway at acycle rate that is directly proportional to said selected speed.
 13. Themethod according to claim 11, wherein said cutting head moves throughsaid continuous pathway in a first direction, as it cuts said groove,wherein said first direction is opposite said selected direction inwhich said cutter head is propelled.
 14. A method of producing rumblestrip grooves in pavement, comprising the steps of: providing a frame;providing a cutting head having a central axis, wherein said cuttinghead is supported by said frame; rotating said cutting head about saidcentral axis; propelling said frame along the pavement in a firstdirection at a selected speed, causing relative movement between saidcutting head and the pavement; periodically bringing said cutting headinto contact with the pavement, wherein said cutting head is movedthrough the pavement in a direction that at least in part compensatesfor said relative movement.
 15. The method according to claim 14,wherein said step of periodically bringing said cutting head intocontact with the pavement includes cycling said central axis of saidcutter head through a continuous pathway, wherein said cutter headcontacts and cuts into the pavement while moving through part of saidcontinuous pathway.
 16. The method according to claim 14, wherein saidstep of propelling said frame includes mounting said frame to a poweredvehicle.
 17. The method according to claim 15, further including thestep of cycling said cutter head through said continuous pathway at acycle rate that is directly proportional to said selected speed.